Conventional hydraulically driven (i.e. hydrostatically controlled) machines such as power lawn mowers include a pair of drive wheels, each of which is independently operated by a hydraulic (i.e. hydrostatic) pump coupled to the mower's engine. A corresponding motor is provided for each drive wheel, each motor being powered and controlled by one of the pumps. Each pump includes a control lever for regulating fluid pressure and direction to its corresponding motor so that the drive wheels can be independently controlled so that each may be rotated at variable speeds in both forward and reverse directions. In this manner, the mower may be steered by controlling the speed and direction of the two drive wheels. This type of design is found in the mower inventions herein.
In certain of the above-identified mowers and in the instant inventions, it is possible to operate one of the drive wheels at a predetermined speed in a first direction and the other drive wheel at the same speed in the opposite direction, thereby enabling the operator to conduct zero-radius turns of the mower. This, of course, provides for improved maneuverability in tight environments. Exemplary zero-radius turning mowers are disclosed in commonly owned U.S. Pat. Nos. 5,507,138 and 5,600,944.
Conventional power mowers are generally divided into three separate categories: (i) self-propelled walk behind mowers; (ii) mowers operated by a seated occupant; and (iii) mowers operated by a standing operator. Walk behind mowers and mowers operated by seated occupants have a number of disadvantages, some of which are discussed in the background section of the parent application, and in the background sections of the above-identified U.S. Pat. Nos. 5,507,138 and 5,600,944, each of which is incorporated herein by reference.
Unfortunately, known prior art mowers which have a platform for supporting a standing operator, such as that disclosed in U.S. Pat. No. 4,878,339, have a number of disadvantages. These include inefficient design, overly complicated design and equipment, the utilization of parts which are not efficiently manufacturable or easily assembled in mass production environments, etc.
It is apparent from the above that there exists a need in the art for a power lawn mower operable by a standing occupant including an efficient and operator-friendly design, and parts therefor which are efficient, easily made, cost-effective, and the like. Each of the above-identified advantages is accomplished herein.
It is a purpose of this invention to fulfill the above-described needs in the art, as well as other needs which will become apparent to the skilled artisan from the following detailed description of this invention.